Psychosocial Working Environment, Submarine Deployment, and Sleep among Navy Submarine Crews: An 8-day Longitudinal Study

Background: Employed as navy submariners is extremely demanding, especially during submarine deployments. The confined spaces and rotating shifts that deviate from a conventional 24-h cycle may disrupt submariners’ sleep–wake cycles, potentially impairing their judgment and health. Aim: This study aimed to examine (1) whether submarine crews’ sleep varied across different submarine deployment stages or shift schedules and (2) the associations between submarine deployment, psychosocial working environment, and their sleep. Methods: A convenience sample of Taiwanese navy submarine crews was recruited. During the 8-day observational longitudinal study, participants completed work logs before sleeping and sleep diaries upon awakening. Generalized estimating equation models were employed for data analysis. Results: Prevalence rates of short sleep duration and poor sleep quality varied across different shifts. Compared to day shifts, the likelihood of short sleep duration (odds ratio [OR] = 0.3, 95% confidence interval [CI] = 0.1, 0.5) and poor sleep quality (OR = 0.4, 95% CI = 0.2, 0.9) was significantly lower on evening shifts. Higher work demands were associated with an increased likelihood of short sleep duration (OR = 1.6, 95% CI = 1.2, 2.2) and poor sleep quality (OR = 1.4, 95% CI = 1.0, 2.0). In addition, days with higher job control were more likely to experience poor sleep quality (OR = 1.7, 95% CI = 1.1, 2.6). Nevertheless, there were no significant correlations between submarine deployment stages and sleep characteristics. Conclusion: This study provides valuable insights into the sleep characteristics of Taiwanese navy submarine crews. Strategies to optimize shift scheduling, reduce stress, or bolster resilience may benefit their sleep health.